anthrax

Anthrax

Definition

Anthrax is an infection caused by the bacterium Bacillus anthracis that primarily affects livestock but that can occasionally spread to humans, affecting either the skin, intestines, or lungs. In humans, the infection can often be treated, but it is almost always fatal in animals.

Description

Anthrax is most often found in the agricultural areas of South and Central America, southern and eastern Europe, Asia, Africa, the Caribbean, and the Middle East. In the United States, anthrax is rarely reported; however, cases of animal infection with anthrax are most often reported in Texas, Louisiana, Mississippi, Oklahoma, and South Dakota. The bacterium and its associated disease get their name from the Greek word meaning "coal" because of the characteristic coal-black sore that is the hallmark of the most common form of the disease.

During the 1800s, in England and Germany, anthrax was known either as "wool-sorter's" or "ragpicker's" disease because workers contracted the disease from bacterial spores present on hides and in wool or fabric fibers. Spores are the small, thick-walled dormant stage of some bacteria that enable them to survive for long periods of time under adverse conditions. The first anthrax vaccine was perfected in 1881 by Louis Pasteur.

The largest outbreak ever recorded in the United States occurred in 1957 when nine employees of a goat hair processing plant became ill after handling a contaminated shipment from Pakistan. Four of the five patients with the pulmonary form of the disease died. Other cases appeared in the 1970s when contaminated goatskin drumheads from Haiti were brought into the U.S. as souvenirs.

Today, anthrax is rare, even among cattle, largely because of widespread animal vaccination. However, some serious epidemics continue to occur among animal herds and in human settlements in developing countries due to ineffective control programs. In humans, the disease is almost always an occupational hazard, contracted by those who handle animal hides (farmers, butchers, and veterinarians) or sort wool. There are no reports of the disease spreading from one person to another.

Anthrax as a weapon

There has been a great deal of recent concern that the bacteria that cause anthrax may be used as a type of biological warfare, since it is possible to become infected simply by inhaling the spores, and inhaled anthrax is the most serious form of the disease. The bacteria can be grown in laboratories, and with a great deal of expertise and special equipment, the bacteria can be altered to be usable as a weapon.

The largest-ever documented outbreak of human anthrax contracted through spore inhalation occurred in Russia in 1979, when anthrax spores were accidentally released from a military laboratory, causing a regional epidemic that killed 69 of its 77 victims. In the United States in 2001, terrorists converted anthrax spores into a powder that could be inhaled and mailed it to intended targets, including news agencies and prominent individuals in the federal government. Because the United States government considers anthrax to be of potential risk to soldiers, the Department of Defense has begun systematic vaccination of all military personnel against anthrax. For civilians in the United States, the government has instituted a program called the National Pharmaceutical Stockpile program in which antibiotics and other medical materials to treat two million people are located so that they could be received anywhere in the country within twelve hours following a disaster or terrorist attack.

Causes and symptoms

The naturally occurring bacterium Bacillus anthracis produces spores that can remain dormant for years in soil and on animal products, such as hides, wool, hair, or bones. The disease is often fatal to cattle, sheep, and goats, and their hides, wool, and bones are often heavily contaminated.

The bacteria are found in many types of soil, all over the world, and usually do not pose a problem for humans because the spores stay in the ground. In order to infect a human, the spores have to be released from the soil and must enter the body. They can enter the body through a cut in the skin, through consuming contaminated meat, or through inhaling the spores. Once the spores are in the body, and if antibiotics are not administered, the spores become bacteria that multiply and release a toxin that affects the immune system. In the inhaled form of the infection, the immune system can become overwhelmed and the body can go into shock.

Symptoms vary depending on how the disease was contracted, but the symptoms usually appear within one week of exposure.

Key terms

Antibody — A specific protein produced by the immune system in response to a specific foreign protein or particle called an antigen.

Spore — A dormant form assumed by some bacteria, such as anthrax, that enable the bacterium to survive high temperatures, dryness, and lack of nourishment for long periods of time. Under proper conditions, the spore may revert to the actively multiplying form of the bacteria.

Cutaneous anthrax

In humans, anthrax usually occurs when the spores enter a cut or abrasion, causing a skin (cutaneous) infection at the site. Cutaneous anthrax, as this infection is called, is the mildest and most common form of the disease. At first, the bacteria cause an itchy, raised area like an insect bite. Within one to two days, inflammation occurs around the raised area, and a blister forms around an area of dying tissue that becomes black in the center. Other symptoms may include shivering and chills. In most cases, the bacteria remain within the sore. If, however, they spread to the nearest lymph node (or, in rare cases, escape into the bloodstream), the bacteria can cause a form of blood poisoning that rapidly proves fatal.

Inhalation anthrax

Inhaling the bacterial spores can lead to a rare, often-fatal form of anthrax known as pulmonary or inhalation anthrax that attacks the lungs and sometimes spreads to the brain. Inhalation anthrax begins with flulike symptoms, namely fever, fatigue, headache, muscle aches, and shortness of breath. As early as one day after these initial symptoms appear, and as long as two weeks later, the symptoms suddenly worsen and progress to bronchitis. The patient experiences difficulty breathing, and finally, the patient enters a state of shock. This rare form of anthrax is often fatal, even if treated within one or two days after the symptoms appear.

Intestinal anthrax

Intestinal anthrax is a rare, often-fatal form of the disease, caused by eating meat from an animal that died of anthrax. Intestinal anthrax causes stomach and intestinal inflammation and sores or lesions (ulcers), much like the sores that appear on the skin in the cutaneous form of anthrax. The first signs of the disease are nausea and vomiting, loss of appetite, and fever, followed by abdominal pain, vomiting of blood, and severe bloody diarrhea.

Diagnosis

Anthrax is diagnosed by detecting B. anthracis in samples taken from blood, spinal fluid, skin lesions, or respiratory secretions. The bacteria may be positively identified using biochemical methods or using a technique whereby, if present in the sample, the anthrax bacterium is made to fluoresce. Blood samples will also indicate elevated antibody levels or increased amounts of a protein produced directly in response to infection with the anthrax bacterium. Polymerase chain reaction (PCR) tests amplify trace amounts of DNA to show that the anthrax bacteria are present. Additional DNA-based tests are also currently being perfected.

Treatment

In the early stages, anthrax is curable by administering high doses of antibiotics, but in the advanced stages, it can be fatal. If anthrax is suspected, health care professionals may begin to treat the patient with antibiotics even before the diagnosis is confirmed because early intervention is essential. The antibiotics used include penicillin, doxycycline, and ciprofloxacin. Because inhaled spores can remain in the body for a long time, antibiotic treatment for inhalation anthrax should continue for 60 days. In the case of cutaneous anthrax, the infection may be cured following a single dose of antibiotic, but it is important to continue treatment so as to avoid potential serious complications, such as inflammation of the membranes covering the brain and spinal cord (meningitis). In the setting of potential bioterrorism, cutaneous anthrax should be treated with a 60-day dose of antibiotics.

Research is ongoing to develop new antibiotics and antitoxins that would work against the anthrax bacteria and the toxins they produce. One Harvard professor, Dr. R. John Collier, and his team have been testing two possible antitoxins on rats. A Stanford microbiologist and a Penn State chemist have also been testing their new antibiotic against the bacteria that cause brucellosis and tularemia, as well as the bacteria that cause anthrax. All of these drugs are still in early investigational stages, however, and it is still unknown how these drugs would affect humans.

Prognosis

Untreated anthrax is often fatal, but death is far less likely with appropriate care. Ten to twenty percent of patients will die from anthrax of the skin (cutaneous anthrax) if it is not properly treated. All patients with inhalation (pulmonary) anthrax will die if untreated. Intestinal anthrax is fatal 25-75% of the time.

Prevention

Anthrax is relatively rare in the United States because of widespread animal vaccination and practices used to disinfect hides or other animal products. Anyone visiting a country where anthrax is common or where herd animals are not often vaccinated should avoid contact with livestock or animal products and avoid eating meat that has not been properly prepared and cooked.

Other means of preventing the spread of infection include carefully handling dead animals suspected of having the disease, burning (instead of burying) contaminated carcasses, and providing good ventilation when processing hides, fur, wool, or hair.

In the event that exposure to anthrax spores is known, such as in the aftermath of a terrorist attack, a course of antibiotics can prevent the disease from occurring.

In the case of contaminated mail, as was the case in the 2001 attacks, the U.S. postal service recommends certain precautions. These precautions include inspecting mail from an unknown sender for excessive tape, powder, uneven weight or lumpy spots, restrictive endorsements such as "Personal," or "Confidential," a postmark different from the sender's address, or a sender's address that seems false or that cannot be verified. Handwashing is also recommended after handling mail. In order to decontaminate batches of mail before being opened, machines that use bacteria-killing radiation could be used to sterilize the mail. These machines are similar to systems already in place on assembly lines for sterile products, such as bandages and medical devices, but this technique would not be practical for large quantities of mail. In addition, the radiation could damage some of the mail's contents, such as undeveloped photographic film. Microwave radiation or the heat from a clothes iron is not powerful enough to kill the anthrax bacteria.

For those in high-risk professions, an anthrax vaccine is available that is 93% effective in protecting against infection. To provide this immunity, an individual should be given an initial course of three injections, given two weeks apart, followed by booster injections at six, 12, and 18 months and an annual immunization thereafter.

Approximately 30% of those who have been vaccinated against anthrax may notice mild local reactions, such as tenderness at the injection site. Infrequently, there may be a severe local reaction with extensive swelling of the forearm, and a few vaccine recipients may have a more general flu-like reaction to the shot, including muscle and joint aches, headache, and fatigue. Reactions requiring hospitalization are very rare. However, this vaccine is only available to people who are at high risk, including veterinary and laboratory workers, livestock handlers, and military personnel. The vaccine is not recommended for people who have previously recovered from an anthrax infection or for pregnant women. Whether this vaccine would protect against anthrax used as a biological weapon is, as yet, unclear.

Wade, Nicholas. "How a Patient Assassin Does Its Deadly Work." New York Times October 23, 2001: Section D, page 1.

anthrax

[an´thraks]

an infectious disease seen most often in cattle, horses, mules, sheep, and goats, due to ingestion of spores of Bacillus anthracis. It can be acquired by humans through contact with infected animals or their byproducts, such as carcasses or skins.

Anthrax in humans usually occurs as a malignant pustule or malignant edema of the skin. In rare instances it can affect the lungs if the spores of the bacillus are inhaled, or it can involve the intestinal tract when infected meat is eaten. The condition often is accompanied by hemorrhage, as the exotoxins from the bacillus attack the endothelium of small blood vessels. The condition is treated by the use of antibiotics such as penicillin and the tetracyclines. The malignant edema can be treated with intravenous hydrocortisone. The disorder is also known by a variety of names, including woolsorters' disease, ragpickers' disease, and charbon.

cutaneous anthrax anthrax due to lodgment of the causative organisms in wounds or abrasions of the skin, producing a black crusted pustule on a broad zone of edema.

gastrointestinal anthrax anthrax due to ingestion of poorly cooked meat contaminated with Bacillus anthracis, with deposition of spores in the submucosa of the intestinal tract, where they germinate, multiply, and produce toxin, resulting in massive edema, which may obstruct the bowel, hemorrhage, and necrosis.

inhalational anthrax a usually fatal form of anthrax due to inhalation of dust containing anthrax spores, which are transported to the regional lymph nodes where they germinate, multiply, and produce toxin, and characterized by hemorrhagic edematous mediastinitis, pleural effusions, dyspnea, cyanosis, stridor, and shock. It is usually an occupational disease, such as in persons who handle or sort contaminated wools and fleeces. Antimicrobial prophylaxis is used to prevent the condition. The Centers for Disease Control and Prevention has published interim guidelines for investigation and response to Bacillus anthracis infection. The evaluation of risk for exposure to aerosolized spores is of highest priority. Obtaining adequate samples, avoiding cross-contamination, and insuring proficient testing and evaluation of test results are all recommended.

meningeal anthrax a rare, usually fatal form of anthrax resembling typical hemorrhagic meningitis due to spread through the bloodstream of Bacillus anthracis from a primary focus of infection; manifestations include cerebrospinal fluid that is hemorrhagic and neurological signs and symptoms.

anthrax

(an'thraks),

Infection by the bacterium Bacillus anthracis, which in humans is caused by contact with infected animals or animal products, and ingestion or inhalation of spores of the bacterium. Worldwide concern is focused on the potential use of anthrax as a bioterrorist weapon, in particular as an inhalational agent. The most common naturally occurring form of human anthrax is the cutaneous, and both the inhalational and gastrointestinal forms are quite rare. Anthrax in animals occurs throughout the world, primarily in herbivores, especially cattle, horses, goats, and sheep.

anthrax

/an·thrax/ (an´thraks) an often fatal, infectious disease of ruminants due to ingestion of spores of Bacillus anthracis in soil; acquired by humans through contact with contaminated wool or other animal products or by inhalation of airborne spores.

cutaneous anthrax that due to inoculation of Bacillus anthracis into superficial wounds or abrasions of the skin, producing a black crusted pustule on a broad zone of edema.

inhalational anthrax a highly fatal form due to inhalation of dust containing anthrax spores, which are transported by alveolar pneumocytes to regional lymph nodes, where they germinate; it is primarily an occupational disease seen in those who handle and sort wools and fleeces.

anthrax

(ăn′thrăks′)

n.

1. A serious infectious disease of mammals caused by the bacterium Bacillus anthracis, most commonly affecting grazing animals. The disease can be transmitted to humans by handling infected animals or contaminated animal products (resulting in cutaneous lesions), by ingesting contaminated meat, or by inhaling bacterial spores.

2. pl.an·thraces(-thrə-sēz′)Archaic A lesion caused by anthrax.

anthrax

[an′thraks/]

Etymology: Gk, anthrax, coal, carbuncle

an acute infectious disease (reportable to public health officials) caused by the spore-forming bacterium Bacillus anthracis and occurring most frequently in herbivores (cattle, goats, sheep). Humans can become infected through skin contact, ingestion, or inspiration of spores from infected animals or animal products. Person-to-person transmission of inhalational disease does not occur. Anthrax in animals is usually fatal. Inspiration causes the most serious form in humans and is usually fatal, but in 95% of the cases it is acquired when a break in the skin has direct contact with infected animals and their hides. The cutaneous form begins with itching and then a 1- to 3-cm reddish brown lesion that ulcerates and then forms dark eschar surrounded by brawny edema; the signs and symptoms that follow include internal hemorrhage, muscle pain, headache, fever, nausea, and vomiting. The pulmonary form, called woolsorter's disease, is often fatal unless treated early. Early symptoms include low-grade fever, nonproductive cough, malaise, fatigue, myalgia, profound sweating, and chest discomfort. Later symptoms include an abrupt onset of a high fever and severe respiratory distress (cyanosis, dyspnea, stridor). Treatment is a 60-day course of antibiotics such as ciprofloxacin, levofloxacin, doxycycline, and penicillin. Contaminated surfaces should be cleaned with a 5% hypochlorite solution. A vaccine is available for veterinarians and for others for whom anthrax is an occupational hazard. The incubation period for anthrax is 7 to 42 days. Anthrax is an important potential bioterrorism agent. Also called malignant edema, malignant pustule, ragpicker disease.

observationsCutaneous anthrax begins as an itchy, raised, red-brown skin bump, which develops into a vesicle and then a painless ulcer with a depressed black necrotic center. Lymph nodes in the adjacent area may be swollen and there may be fever, fatigue, and headache. Eschar from the ulcer dries and drops off with little or no scarring after 1 to 2 weeks. Cutaneous forms respond readily to treatment, but 20% of untreated cases result in death. Inhalation anthrax starts with a brief prodrome that resembles a viral respiratory illness followed by hypoxia, dyspnea, fever, muscle aches, headaches, and fatigue. Once the spores travel to the lymphatic system, respiratory failure and shock occur and death usually ensues regardless of treatment. Gastrointestinal anthrax presents with severe abdominal pain, fever, fatigue, anorexia, hematemesis, and bloody diarrhea. In some cases there may be lesions in the nose, mouth, and throat. The disease spreads systemically and is fatal in 30% to 60% of cases if not treated immediately. Diagnosis in all forms is made by history of possible exposure; by physical exam for presenting symptomatology and by isolation of Bacillus anthracis in blood, skin lesions, or respiratory secretions. Serological testing with enzyme-linked immunosorbent assay can confirm diagnosis. An anthracis test (available in specialized labs) can be used to detect anthrax cell-mediated immunity. Chest x-rays may detect mediastinal widening, pleural effusion, and infiltrates in inhalation anthrax.

interventions Antiinfectives, such as penicillin, doxycycline, Cipro, and/or Floxin, are primary treatment. IV hydration and ventilator support are used for the inhalation form. Local and state authorities need to be notified in all suspected cases. Use of the anthrax vaccine is recommended in limited use for those at risk (e.g., military personnel, veterinarians, and livestock handlers). Side effects are high and schedule is six doses over an 18-month period. Treatment for exposure is usually a post exposure anthrax vaccine and 60-day course of antibiotics.

nursing considerations Nursing care for inhalation anthrax is largely supportive and centers on management of airway and mechanical ventilation, fluid management, and comfort measures. Every member of the health care team should be prepared for an effective response should anthrax be used in a bioterrorism event. This includes familiarization of institution policies, procedures, and protocols, and maintenance of current knowledge regarding bioterrorism threats.

Once common among handlers of infected animals, eg farmers, woolsorters, tanners, brushmakers and carpetmakers in an era when brushes were from animals Clinical Carbuncle–a cluster of boils, that later ulcerates, resulting in a hard black center surrounded by bright red inflammation; rare cases which become systemic are almost 100% fatal

A rare, usually fatal complication of GI or inhalation anthrax with death occurring 1 to 6 days after onset of illness Clinical Meningeal symptoms, nuchal rigidity, fever, fatigue, myalgia, headache, N&V, agitation, seizures, delirium, followed by neurologic degeneration and death

.

an·thrax

(an'thraks)

A disease in humans caused by infection with Bacillus anthracis; marked by hemorrhage and serous effusions in various organs and body cavities and by symptoms of extreme prostration.

[G. anthrax (anthrak-), charcoal, coal, a carbuncle]

anthrax

(an'thraks?) [Gr. anthrax, coal, carbuncle]

ANTHRAX: Cutaneous anthrax lesion on the neck (SOURCE: Centers for Disease Control and Prevention)

An acute infectious disease caused by contact with, ingestion of, or inhalation of the spores of Bacillus anthracis. People who work with contaminated textiles or animal products usually contract it from skin contact with animal hair, hides, or waste (the most common form of the disease, accounting for 95% of cases), but the bacilli may cause a fatal pneumonia if they are inhaled. See: illustration

Immunization

The anthrax bacillus has been prepared in aerosol form for use in biological warfare. As a result, some American troops have been vaccinated against the disease during their military training with one of several evolving vaccines. The effectiveness of the vaccine in disease prevention remains uncertain. Vaccination is also given to patients affected by active anthrax to prevent relapses.biological warfare;

Diagnosis

Diagnosis is made by isolating B. anthracis from blood, sputum, or skin lesion cultures.

Symptoms

Signs and symptoms usually occur within 1 to 7 days after exposure, but can take up to 60 days. Early treatment helps to reduce fatalities. Cutaneous anthrax presents with small, pruritic lesions similar to insect bites that progress to malignant pustules (large, painless boils), vesicles, or skin ulcers with necrotic centers and surrounding brawny edema, usually on an exposed body surface, such as the skin of the hand. Mortality is about 20% from untreated cutaneous anthrax and is less than 1% when treated with an antibiotic (penicillin, doxycycline, ciprofloxacin). GI anthrax involves acute inflammation of the intestinal tract from ingestion of anthrax spores. Symptoms include nausea and vomiting, decreased appetite and fever, progressing to abdominal pain, vomiting blood, and severe to bloody diarrhea. Antibiotic therapy limits mortality to from 25% to 60%. Inhalation anthrax (also called pulmonary anthrax or Woolsorter's disease) is marked by flulike symptoms progressing to fevers, sweats, cough, weakness, and rapidly developing respiratory failure, septic shock, and/or meningitis. Infection of the lungs may be suggested by the rapid onset of respiratory symptoms and chest x-ray or CT findings that may include widening of the mediastinum with hemorrhagic lymph nodes, hilar fullness, and pleural effusion. The disease is often fatal even with the appropriate antibiotic therapy.

Treatment

Persons exposed to anthrax (e.g., after its dissemination by bioterrorists) should receive a 60- to 100-day course of preventive therapy with ciprofloxacin, doxycycline, or penicillin G procaine. Individuals who have active infection with anthrax should receive two of the following antibiotics for a 60-day period: aminoglycosides, penicillin G (or amoxicillin), chloramphenicol, ciprofloxacin, doxycycline, imipenem or meropenem, rifampin, tetracycline, or vancomycin. Patients with pleural effusion benefit from drainage of the effusion with a chest tube.

Patient care

Health supervision is provided to at-risk employees, along with prompt medical care of all lesions. Terminal disinfection of textile mills contaminated with B. anthracis is supervised, using vaporized formaldehyde or other recommended treatment. All cases of anthrax (in livestock or people) are reported to local health authorities. Isolation procedures (mask, gown, gloves, hand hygiene, and incineration of contaminated materials) are maintained to protect against drainage secretions for the duration of illness in inhalation, GI, and cutaneous anthrax. For patients with inhalation anthrax, vital signs are monitored and respiratory support is provided. For patients with cutaneous anthrax, lesions are kept clean and covered with sterile dressings. Prescribed antibiotics are administered and the patient is assessed for desired and adverse effects. Frequent oral hygiene and skin care are provided. Oral fluid intake and frequent small, nutritious meals are encouraged.

anthrax

A serious infection of skin, intestine or lungs caused by spores of Bacillus anthracis which can be transmitted to man from infected animals or animal products. There are large and damaging BOILS, severe GASTROENTERITIS and an often fatal PNEUMONIA. Anthrax has been intensively investigated as a bacteriological weapon and concern has been expressed over its suitability as a terrorist weapon. From the Greek anthrax , coal, possibly because of the black centre and the surrounding redness of the skin lesions.

anthrax

a fever of the spleen in cattle and sheep caused by toxins released from the bacterium Bacillus anthracis. The disease can spread to humans when infected animal products such as wool and bristles are handled, giving rise to malignant skin lesions and pustules.

an·thrax

(an'thraks)

A disease in humans caused by infection with Bacillus anthracis; marked by hemorrhage and serous effusions and symptoms of extreme prostration.

[G. anthrax (anthrak-), charcoal, coal, a carbuncle]

anthrax (an´thraks),

n an infectious disease in herbivorous animals caused by a spore-forming Bacillus organism. Primary lesions in human beings may be on the lips or cheeks.

anthrax

a peracute disease of all animal species, caused by Bacillus anthracis, and characterized by septicemia and sudden death. The causative bacteria form long-living spores which maintain the disease on a farm for many years. Significant necropsy findings include exudation of dark, tarry blood from the body orifices, failure of the blood to clot, absence of rigor mortis and splenomegaly. A dangerous zoonosis. Easily controlled by vaccination of livestock.

alimentary anthrax

infection resulting from the ingestion of animals dead of anthrax. Largely a human manifestation in developing countries.

anthrax belt

regions where anthrax is enzootic, where soil and climate favor persistence of the organism in soil and where routine efforts to control the disease are not sufficient. Outbreaks commonly follow climatic extremes of flood or drought.

cutaneous anthrax

anthrax due to lodgment of the causative organisms in wounds or abrasions of the skin, producing a black crusted pustule on a broad zone of edema. A common form of the disease in humans.

pulmonary anthrax

infection of the respiratory tract resulting from inhalation of dust or animal hair containing spores of Bacillus anthracis; an occupational disease of humans usually affecting those who handle and sort wools and fleeces (woolsorters' disease).

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